Miner&#39;s drill



S. T. SKEEN.

MINERS DRILL.

APPLICATION FlLED OCT 10, 1919. 1,386,434. Patented Aug. 2, 1921, 31 -1- 31 1 WITNESS.

INVENTOR. 5'. 7. Skeefi, BY W W UNITED STATES PATENT OFFICE.

SAMUEL T. SKEEN, OF SANDOVAL, ILLINOIS, ASSIGNOR OF ONE-HALF 'IO CHARLES E. STEAD, OF CENTRALIA, ILLINOIS.

MINERS DRILL.

Application filed October 10, 1919.

To all whom it may concern:

Be it known that I, SAMUEL T. SKJBEN, a citizen of the United States of America, a resident of Sandoval, in the county of Marion, State of Illinois, have invented certain new and useful Improvements in Miners Drills, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to a drill intended more especially for use in drilling coal in deposits thereof in the earth, the present improvement pertaining to a double bladed bit detachably secured to a stem to permit of its removal and detachment, or replacement by another hit of like form.

Figure I is an elevation of my drill looking at the side of the bit.

Fig. II is an elevation looking at the edge of the bit. I

Fig. III isa cross section taken on line IIIIII, Fig. I.

In the drawings A designates a suitable drill stem which is preferably of spiral form, as is usual in miners drills.

The stem A is reduced in size at the end which receives the bit to provide a reduced shank 1, and adjacent to the edges of said shank at the end of the stem are abutments .2 against which the bit to be hereinafter described is adapted to rest.

B designates a double bladed bit comprising blades 3, spaced from each other a distance corresponding approximately to the thickness of the shank 1 of the drill stem A, the blades being joined by a transverse base web 4. The said base web contains a perforation 5 of a size corresponding approximately to the size of the shank 1, which permits of the web being moved inwardly along said shank until the web rests in contact with the abutments 2 at the end of the stem A.

The portions of the blades 3 contiguous to the base web 4 lie parallel with each other and therefore, when the bit B is fitted to the shank on the stem A, said portions are parallel with said shank and they embrace the shank. One blade has a cutter. portion which extends laterally in one direction and the other blade has a cutter portion which extends laterally in a direction opposite to the direction of extension of the first blade.

Specification of Letters Patent.

Patented Aug. 2, 1921.

Serial No. 329,852.

Each blade is preferably twisted, as seen in Fig. II, and has a side cutting edge and an end cutting edge. The blades are preferably of concave form, or cupped, so that the cutting edges willconstantly travel ahead of the central portions of the blades and the material cut thereby will feed inwardly along the concave surfaces to pass more readily from the bit to the spiral stem, thereby constantly relieving the blades of resistance offered by the material cut and making the drilling operation easier.

The bit B is securely attached to the shank 1 of the stem A by a bolt 6, or other suitable means of fastening extending through the two blades of the bit and the shank, said fastening means not only serving to detachably secure the bit to the stem but also to hold the base web of the bit in contact with the abutments 2 at the end of the stem A, so that said abutments will receive the end thrust of the bit, thereby relieving the fastening means from the strain which would otherwise be imposed thereon during cutting action.

I claim:

1. A drill comprising a stem having a noncircular bit-receiving shank at one of its ends and provided with end abutments adjacent said shank, and a double bladed bit secured to and embracing said non-circular shank, said bit abutting against the abutments at the end of said stem.

2. A drill comprising a stem having a noncircular bit-receiving shank at one of its ends, a double bladed bit having an apertured base web connecting its blades, said web being fitted to said shank and the blades abutting and embracing the shank, and means for detachably securing said bit to said shank.

3. A drill comprising a stem having a reduced bitreceiving shank at one of its ends and provided with end abutments adjoining said shank, a double bladed bit having an apertured base web surrounding said shank and resting against said abutments, and fastening means extending through both blades of the bit and said shank whereby the bit is secured to the shank and held in embracing relation therewith.

In testimony that I claim the foregoing I hereunto afiix my signature.

SAMUEL T. SKEEN. 

